If you're handy and can find a chimney sweep to inspect your work, you can buy a stainless liner, with insulation for probably around a grand. Having someone else do it is going to be more expensive but has a better chance of making your insurance company happy.
I like the quadrafires but have a question. How's your wood supply? Have you already got multiple full (not face) cords cut/split/stacked that have been in the wind long enough to have moisture content lower than 25 percent? If not, you're going to be miserable trying to heat your home with an EPA certified stove. Where do you live? I may have another suggestion, if you're open to it...